get_listing_prices

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations and no output schema, the description carries the full burden and does so well: it discloses the return shape (one entry per listing type with sale fee percentage, fee amount and flags) and that omitted listing_type_id yields all types. It omits any note on permissions, idempotency, or currency/price-error behavior, which keeps it from a 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, front-loaded with the core action, then timing guidance, then return shape — nothing redundant except a mild restatement between "BEFORE create_item" and "before committing." Well sized for the tool's complexity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only, three-parameter estimate with no output schema or annotations, the description covers what the tool does, when to call it, and what comes back. It is nearly complete; only permission/error context (e.g. invalid price or category handling) is absent, which is minor for a low-risk estimation call.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already explains price, category_id and listing_type_id, including the omit-to-get-all-types behavior. The description restates the same semantics ("optionally for a specific category and listing type") without adding syntax, valid values, or edge cases beyond the schema, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a precise action and object ("Estimate the selling fees for publishing an item at a given price") and even corrects the misleading tool name, which sounds like it returns listing prices rather than a fee estimate. It clearly separates itself from siblings like create_item and get_listing_types by naming the fee-estimation scope.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives explicit sequencing guidance: "Use this BEFORE create_item," so the seller knows the commission cost per exposure plan before committing. It does not state when not to use it or name a direct alternative with comparable output, so it falls just short of the top score.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.